Atomic-scale visualization of antisite defects in LiFePO4
Atomic-scale visualization of antisite defects in LiFePO4
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DOI：
10.1103/physrevlett.100.125502
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发表时间：
2008-03-28
影响因子：
8.6
通讯作者：
Ikuhara, Yuichi
中科院分区：
文献类型：
--
作者：
Chung, Sung-Yoon;Choi, Si-Young;Ikuhara, Yuichi
我们可视化反位交换缺陷LiFePO4晶体有序橄榄石结构，通过使用环形暗场扫描透射电子显微镜（STEM）。在较低温度下退火的样品中，在STEM图像的一些Li柱中观察到可识别的明亮对比度，这直接证明了Fe原子的无序占位。此外，这种交换缺陷似乎是局部聚集，而不是均匀地分散在晶格中，虽然它们的总浓度是相当低的。本研究强调了原子级观测对宏观分析方法无法预测的缺陷分布的重要性。
We visualize the antisite exchange defects in LiFePO4 crystals with an ordered olivine structure by using annular dark-field scanning transmission electron microscopy (STEM). A recognizable bright contrast is observed in some of the Li columns of STEM images in a sample annealed at a lower temperature, which directly demonstrates the disordered occupations by Fe atoms. Furthermore, such exchange defects appear to be locally aggregated rather than homogeneously dispersed in the lattice, although their overall concentration is fairly low. The present study emphasizes the significance of atomic-level observations for the defect distribution that cannot be predicted by macroscopic analytical methods.